ISSN:
1741-0444
Keywords:
Atherosclerosis
;
Attenuation
;
Broadband pulsed ultrasounds
;
Phase-cancellation artefacts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract The study was designed to establish whether changes in arterial wall structure due to atherosclerosis may be reflected in the increase of ultrasonic attenuation. Accordingly, fresh aortic wall specimens were analysed by an attenuation technique and pathologically classified into three groups: normal, fibrofatty and calcific. Analysis was performed by using a single broadband transducer acting as transmitter and receiver of the echo produced by a specular reflector positioned behind the specimen under study. Two indices were derived from the transfer function H(f) of the specimen: the slope of the best-fit straight line to In |H(f)| and the absolute value of In |H(f)| at 9MHz. The index based on the slope of In |H(f)| is able to distinguish normal wall from atherosclerotic lesions. The absolute value of In |H(f)| is able to differentiate normal, fibrofatty and calcific groups. However, such an index is strongly influenced by specular reflections at water/specimen interfaces. Acquisition of ultrasonic echoes was improved with the use of a small-diameter transducer, which is presumed to reduce distortion in the transfer function due to phase-cancellation effects. According to a statistical test based on the evaluation of the goodness of the straight-line fit to In |H(f)|, the results of the two sets of measurements were compared. The importance of a small-diameter transducer for the further reduction of phase-cancellation artefacts was assessed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02446861
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